Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)

What happens in IIH

Cerebrospinal fluid (CSF) surrounds the brain and spinal cord. In IIH, CSF pressure rises, possibly because of reduced drainage of fluid into the veins, narrowing of the large veins that drain the brain, and hormonal and metabolic factors linked to obesity. The raised pressure pushes on the optic nerves at the back of the eyes, causing swelling (papilledema). Over time, the nerve fibers can be damaged, leading to permanent loss of side vision and, in severe cases, blindness.

The term "pseudotumor" means "false tumor": the symptoms resemble those of a brain tumor, but no tumor is present.

Risk factors and causes

• Female sex and age 20 to 45
• Obesity or recent weight gain. Even modest weight gain can trigger it
• Polycystic ovary syndrome and hormonal conditions
• Medicines: tetracycline antibiotics (doxycycline, minocycline), isotretinoin and high-dose vitamin A, growth hormone, lithium, and stopping steroids
• Sleep apnea
• Kidney disease, anemia and some endocrine disorders

When a specific cause such as a medicine or blocked vein is found, the condition is called secondary intracranial hypertension.

Symptoms

• Headache: daily, often pressure-like, worse in the morning, lying down or with coughing and straining
• Pulsatile tinnitus: a whooshing sound in the ears in time with the heartbeat
• Transient visual obscurations: brief graying or blackouts of vision lasting seconds, often on standing
• Blurred vision and loss of side vision
• Double vision, often horizontal, from pressure on the sixth cranial nerve
• Neck, shoulder and back pain
• Nausea
• Some people, especially men, have few headaches and present with vision loss

Diagnosis

• Eye examination: looking for papilledema, measuring visual acuity and visual fields. Optical coherence tomography (OCT) measures optic nerve swelling.
• MRI of the brain with MR venography: rules out a tumor, hydrocephalus and cerebral venous thrombosis, which can cause identical symptoms. Narrowing of the transverse venous sinuses is often seen in IIH.
• Lumbar puncture: measures the opening pressure of CSF. In adults, a pressure above 25 cm of water, with normal fluid composition, supports the diagnosis.
• Blood tests and medication review for secondary causes.

Treatment

Weight loss

Losing about 5 to 15 percent of body weight often lowers pressure, reduces headaches and improves papilledema. Options include diet programs, medicines for weight loss, and bariatric surgery, which is highly effective for people with obesity and persistent IIH.

Medicines

• Acetazolamide: reduces CSF production. It is the main first-line medicine. Side effects include tingling in the hands and feet, altered taste of carbonated drinks, tiredness and kidney stones.
• Topiramate: also reduces CSF production and may help weight loss and headaches.
• Headache treatment: with care to avoid medication overuse headache.

Surgery and procedures

For vision loss that worsens despite treatment:

• CSF shunting: a tube drains CSF from the brain or spine to the abdomen.
• Venous sinus stenting: a stent opens narrowed drainage veins in the brain.
• Optic nerve sheath fenestration: a small window cut in the sheath around the optic nerve to relieve pressure.

Stop triggering medicines

Stopping tetracyclines, isotretinoin or vitamin A when they are the cause.

Monitoring

Regular eye examinations with visual field testing are essential, as vision changes can occur without obvious symptoms. Frequency depends on severity.

Outlook

With treatment, most people's vision is preserved and papilledema improves. Headaches may persist and can need separate management. Recurrence is possible with weight regain. Permanent vision loss occurs in a minority, mainly when diagnosis or treatment is delayed.

Frequently asked questions

What is pseudotumor cerebri?

Pseudotumor cerebri, or idiopathic intracranial hypertension, is a condition in which pressure inside the skull is high without a tumor or other visible cause. It causes headaches, a pulsing sound in the ears and vision problems, and mostly affects women of childbearing age with excess weight.

What are the symptoms of idiopathic intracranial hypertension?

Common symptoms include daily headaches, a whooshing sound in the ears in time with the heartbeat, brief episodes of dimmed vision, blurred or double vision, neck and back pain, and nausea. An eye doctor may see swelling of the optic nerves.

Can pseudotumor cerebri cause blindness?

Yes, if untreated. Raised pressure damages the optic nerves, causing gradual loss of side vision and, in severe cases, blindness. Regular eye exams and prompt treatment with weight loss, medicines or surgery prevent vision loss in most people.

How is pseudotumor cerebri treated?

Treatment includes weight loss, medicines such as acetazolamide or topiramate that lower spinal fluid pressure, stopping triggering medicines, and treating headaches. If vision worsens despite treatment, surgery such as a shunt, venous sinus stenting or optic nerve sheath fenestration may be needed.